The conventional hand tools, such as a hammer, a wrench, a hatchet, etc., are formed of a head and a handle fastened at one end thereof with the head. The head may be of various shapes, depending on the nature of the hand tool. The handle of the conventional hand tool may be made of a wooden rod, a metal bar, or a metal bar which is provided. with a protective jacket of a plastic or rubber material. The protective jacket is generally formed by injection molding. The protective jacket may be made separately and then fitted over the handle in conjunction with an adhesive. The protective jacket of the conventional hand tool is prone to become detached from the handle.